This invention relates, in general, to textile fabric, and more particularly, to a process for heat treating textile material webs, especially knit fabric, on finishing machines.
In the treatment of textile material webs, as the same are passed through finishing machines, such webs are heated, as under the influence of steam, hot air, or other suitable sources of heat. In those cases in which, for example, knit fabric provided with ribbed edges is so treated, the elasticity and springiness of such edges are damaged under the influence of heat and this is particularly so if the knit fabric or the ribbed edges thereof consist of fibers having a low melting point, as, for example, being formed of acrylic resins or acrylic blends.
It is known that one may utilize mechanical protective means in the form of covering materials or plates disposed upon tensioning frames or other conveyor belt systems in order to avoid the undesired change in the properties of the fibers in the region of the ribbed edges. However, mechanical protective means of this type require comparatively extensive effort and have proved markedly expensive thereby complicating the design of the machine as well as the operating thereof.
Therefore, it is an object of the present invention to effect protection of specific regions of textile material webs during the treatment thereof on finishing machines, from the influence of steam, hot air, or other sources of heat in a relatively inexpensive manner, whereby the use of mechanical covering elements for protective purposes may be eliminated.
It is a further object of the present invention to provide a method for protecting specific regions of textile material webs from being damaged under the influence of heat during transmission in finishing machines by suitably reducing the temperature of such regions so that the subsequent elevation by the heat treatment will not reach the degree at which damage is caused.
It is a further object of the present invention to provide a method of the character stated which may be easily effected and which does not require the utilization of costly agents.
Essentially, the method of this invention is advantageously accomplished by cooling or chilling the particular regions of the web to be protected to such a low temperature that during the subsequent heat transmission as in a finishing machine will only effect a reheating to a level that is not damaging or detrimental to the erstwhile cooled or chilled web portion.